1. Field of the Invention
The invention relates to an ATM exchange and, in particular, to a PNNI routing computation system applied to the ATM exchange.
2. Description of the Related Art
Generally, in an ATM exchange, PNNI (Private Network-Network Interface) routing computation is performed before receiving of a call and the computation results are stored as pre-computed routes. Therefore, the computation can realize a rapid process of the ATM exchange.
For example, when the ATM exchange receives a call, if a proper route satisfying a QoS requirement of the call is found among the pre-computed routes, the proper route is used to establish a connection route of the call. Otherwise, a proper route is further determined by performing additional routing computation.
Also, in the PNNI routing computation, a route in a network is decided by using a sort of routing protocol (logic) which is incorporated into the ATM exchange in advance.
Therefore, when calls to be sent to the same destination are received in the same ATM exchange, the calls are sent via the same route. That is, it is difficult to select a route among a plurality of candidate routes according to an object of the call.
For example, a certain subscriber might require a network administrator to use a route which realizes the minimum CTD (Cell Transfer Delay) with regard to a response delay. On the other hand, another subscriber might require the network administrator to use a reliable route or to select a route which passes through ATM exchanges and which has a high reliability. At any rate, it is desirable to individually select a proper route which is fit for a purpose of the subscriber.
However, to select the proper routes, the network administrator must produce a connection by directly designating ATM exchanges and links which are included in the connection, and thus huge operating load and cost are imposed on the network administrator.
It is, therefore, an object of the invention to provide a PNNI routing computation system which can select, at an ATM exchange, a single route from a plurality of routes for calls which are received in the ATM exchange.
In other words, it is an object of the invention to provide a PNNI routing computation system which can establish a connection route satisfying a variety of subscriber""s requirements of network.
According to a first aspect of the invention, there is provided a PNNI routing computation system which is used in a PNNI network including a plurality of ATM exchanges connected each other via links, and which performs PNNI routing computation on establishing a connection between subscribers. Herein, each ATM exchange comprises a storage unit which stores the plural types of weight values for each link, a computing unit which computes total weight value for each possible PNNI route between the subscribers by referring to one of the types of weight values selected by a calling subscriber, and a selecting unit which selects a route having the minimum total weight value among the possible PNNI routes as a result of the PNNI routing computation.
According to a second aspect of the invention, there is provided a PNNI routing computation system which is used in a PNNI network including a plurality of ATM exchanges connected each other via links, and which performs PNNI routing computation on establishing a connection between subscribers. Herein, each ATM exchange comprises a storage unit which stores the plural types of weight values for each link, a computing unit which computes total weight value for each possible PNNI route between the subscribers by referring to one of the types of weight values selected by a calling subscriber, and a selecting unit which selects a route having the minimum total weight value among the possible PNNI routes as a result of the PNNI routing computation, wherein the types of the weight values include a type of weight values based on administrative weight (AW) and a type of weight values based on cell transfer delay (CTD).
According to a third aspect of the invention, there is provided a PNNI routing computation system which is used in a PNNI network including a plurality of ATM exchanges connected each other via links, and which performs PNNI routing computation on establishing a connection between subscribers. Herein, each ATM exchange comprises a first storage unit which stores plural types of weight values for each link, the plural types of weight values being provided by a subscriber accommodated in the ATM exchange, a network information process unit which exchanges the plural types of weight values to the next ATM exchanges to obtain the plural types of weight values for all links of the PNNI network and stores the weight values obtained from the next ATM exchanges into the first storage unit, a computing unit which computes total weight values for all possible PNNI routes from the ATM exchange to one of the other ATM exchanges by referring to the plural types of weight values stored in the first storage unit, and a second storage unit which stores the computed total weight values for each PNNI route.
According to a fourth aspect of the invention, there is provided a PNNI routing computation system which is used in a PNNI network including a plurality of ATM exchanges connected each other via links, and which performs PNNI routing computation on establishing a connection between subscribers. Herein, each ATM exchange comprises a first storage unit which stores plural types of weight values for each link and a type of the weight values used for routing computation, the plural types of weight values and the type used for routing computation being provided by a subscriber accommodated in the ATM exchange, a network information process unit which exchanges the plural types of weight values to the next ATM exchanges to obtain the plural types of weight values for all links of the PNNI network and stores the weight values obtained from the next ATM exchanges into the first storage unit, a computing unit which computes total weight value for all possible PNNI routes from the ATM exchange to one of the other ATM exchanges by referring to the plural types of weight values stored in the first storage unit, a second storage unit which stores the computed total weight values for each PNNI route, and a first call process unit which, when a subscriber accommodated in an ATM exchange including the first call process unit issues a call request, selects a PNNI route having the minimum total weight value from the second storage unit based on the type of weight values provided by the calling subscriber.
According to a fifth aspect of the invention, there is provided a method of a PNNI routing computation on establishing a connection between subscribers in ATM exchanges which are included in a PNNI network and are connected each other via links. The method comprises the steps of computing total weight value for each possible PNNI route between the subscribers by referring to one of types of weight values selected by a calling subscriber, (each of the weight values corresponding to the link), and selecting a route having the minimum total weight value among the possible PNNI routes.
According to a sixth aspect of the invention, there is provided a method of a PNNI routing computation on establishing a connection between subscribers in ATM exchanges which are included in a PNNI network and are connected each other via links. The method comprises the steps of exchanging plural types of weight values each of which corresponds to a link and which are provided in a subscriber accommodated in the ATM exchange, to the next ATM exchanges to obtain the plural types of weight values for all links of the PNNI network, computing total weight values for all possible PNNI routes from the ATM exchange to one of the other ATM exchanges by referring to the obtained plural types of weight values, and storing the computed total weight values for each PNNI route.
According to a seventh aspect of the invention, there is provided a recording medium readable by a computer, tangibly embodying a program of instructions executable by the computer to perform a method of a PNNI routing computation on establishing a connection between subscribers in ATM exchanges which are included in a PNNI network and are connected each other via links. The method comprises the steps of computing total weight value for each possible PNNI route between the subscribers by referring to one of types of weight values selected by a calling subscriber, (each of the weight values corresponding to the link), and selecting a route having the minimum total weight value among the possible PNNI routes.
According to an eighth aspect of the invention, there is provided a computer data signal embodied in a carrier wave and representing a sequence of instructions which, when executed by a processor, cause the processor to perform a method of a PNNI routing computation on establishing a connection between subscribers in ATM exchanges which are included in a PNNI network and are connected each other via links. The method comprises the steps of computing total weight value for each possible PNNI route between the subscribers by referring to one of types of weight values selected by a calling subscriber, (each of the weight values corresponding to the link), and selecting a route having the minimum total weight value among the possible PNNI routes.
According to a ninth aspect of the invention, there is provided a program Product comprising, computer readable instructions and a recording medium bearing the computer readable instructions. And the instructions are adaptable to enable a computer to perform a method of a PNNI routing computation on establishing a connection between subscribers in ATM exchanges which are included in a PNNI network and are connected each other via links. The method comprises the steps of computing total weight value for each possible PNNI route between the subscribers by referring to one of types of weight values selected by a calling subscriber, (each of the weight values corresponding to the link), and selecting a route having the minimum total weight value among the possible PNNI routes.
According to a tenth aspect of the invention, there is provided a recording medium readable by a computer, tangibly embodying a program of instructions executable by the computer to perform a method of a PNNI routing computation on establishing a connection between subscribers in ATM exchanges which are included in a PNNI network and are connected each other via links. The method comprises the steps of exchanging plural types of weight values each of which corresponds to a link and which are provided in a subscriber accommodated in the ATM exchange, to the next ATM exchanges to obtain the plural types of weight values for all links of the PNNI network, computing total weight values for all possible PNNI routes from the ATM exchange to one of the other ATM exchanges by referring to the obtained plural types of weight values, and storing the computed total weight values for each PNNI route.
According to an eleventh aspect of the invention, there is provided a computer data signal embodied in a carrier wave and representing a sequence of instructions which, when executed by a processor, cause the processor to perform a method of a PNNI routing computation on establishing a connection between subscribers in ATM exchanges which are included in a PNNI network and are connected each other via links. The method comprises the steps of exchanging plural types of weight values each of which corresponds to a link and which are provided in a subscriber accommodated in the ATM exchange, to the next ATM exchanges to obtain the plural types of weight values for all links of the PNNI network, computing total weight values for all possible PNNI routes from the ATM exchange to one of the other ATM exchanges by referring to the obtained plural types of weight values, and storing the computed total weight values for each PNNI route.
According to a twelfth aspect of the invention, there is provided a Program comprising, computer readable instructions and a recording medium bearing the computer readable instructions. And the instructions are adaptable to enable a computer to perform a method of a PNNI routing computation on establishing a connection between subscribers in ATM exchanges which are included in a PNNI network and are connected each other via links. The method comprises the steps of exchanging plural types of weight values each of which corresponds to a link and which are provided in a subscriber accommodated in the ATM exchange, to the next ATM exchanges to obtain the plural types of weight values for all links of the PNNI network, computing total weight values for all possible PNNI routes from the ATM exchange to one of the other ATM exchanges by referring to the obtained plural types of weight values, and storing the computed total weight values for each PNNI route.
According to a thirteenth aspect of the invention, there is provided a routing computation system which is used in an IP network including a plurality of routing devices connected to each other via links, and which performs a routing computation on establishing a connection between subscribers. Herein, each routing device comprises a storage unit which stores plural types of weight values for each link, a computing unit which computes total weight value for each possible route between the subscribers by referring to one of the types of weight values selected by a calling subscriber, and a selecting unit which selects a route having the minimum total weight value among the possible PNNI routes as a result of the routing computation.
According to a fourteenth aspect of the invention, there is provided a routing computation system which is used in an IP network including a plurality of routing devices connected each other via links, and which performs a routing computation on establishing a connection between subscribers. Herein, each routing device comprises a storage unit which stores the plural types of weight values for each link, a computing unit which computes total weight value for each possible route between the subscribers by referring to one of the types of weight values selected by a calling subscriber, and a selecting unit which selects a route having the minimum total weight value among the possible PNNI routes as a result of the routing computation, wherein the types of the weight values include a type of weight values based on administrative weight (AW) and a type of weight values based on cell transfer delay (CTD).
According to a fifteenth aspect of the invention, there is provided a routing computation system which is used in an IP network including a plurality of routing devices connected each other via links, and which performs a routing computation on establishing a connection between subscribers. Herein, each routing device comprises a first storage unit which stores plural types of weight values for each link, the plural types of weight values being provided by a subscriber accommodated in the routing device, a network information process unit which exchanges the plural types of weight values to the next routing devices to obtain the plurality types of weight values for all links of the IP network and stores the weight values obtained from the next routing devices into the first storage unit, a computing unit which computes total weight values for all possible routes from the routing device to one of the other routing devices by referring to the plural types of weight values stored in the first storage unit, and a second storage unit which stores the computed total weight values for each route.
According to a sixteenth aspect of the invention, there is provided a routing computation system which is used in an IP network including a plurality of routing devices connected to each other via links, and which performs a routing computation on establishing a connection between subscribers. Herein, each routing device comprises a first storage unit which stores plural types of weight values for each link and a type of the weight values used for routing computation, the plural types of weight values and the type used for routing computation being provided by a subscriber accommodated in the routing device, a network information process unit which exchanges the plural types of weight values to the next routing devices to obtain the plural types of weight values for all links of the IP network and stores the weight values obtained from the next routing devices into the first storage unit, a computing unit which computes total weight value for all possible routes from the routing device to one of the other routing devices by referring to the plural types of weight values stored in the first storage unit, a second storage unit which stores the computed total weight values for each route, and a first call process unit which, when a subscriber accommodated in a routing device including the first call process unit issues a call request, selects a route having the minimum total weight value from the second storage unit based on the type of weight values provided by the calling subscriber.
According to a seventeenth aspect of the invention, there is provided a method of an IP routing computation on establishing a connection between subscribers in routing devices which are included in an IP network and are connected each other via links. The method comprises the steps of computing total weight value for each possible route between the subscribers by referring to one of types of weight values selected by a calling subscriber, each of the weight values corresponding to the link, and selecting a route having the minimum total weight value among the possible routes.
According to an eighteenth aspect of the invention, there is provided a method of an IP routing computation on establishing a connection between subscribers in routing devices which are included in an IP network and are connected each other via links. The method comprises the steps of exchanging plural types of weight values each of which corresponds to a link and which are provided in a subscriber accommodated in the routing device, to the next routing devices to obtain the plural types of weight values for all links of the IP network, computing total weight values for all possible routes from the routing device to one of the other routing devices by referring to the obtained plural types of weight values, and storing the computed total weight values for each route.
According to a nineteenth aspect of the invention, there is provided a computer data signal embodied in a carrier wave and representing a sequence of instructions which, when executed by a processor, cause the processor to perform a method of an IP routing computation on establishing a connection between subscribers in routing devices which are included in an IP network and are connected each other via links. The method comprises the steps of exchanging plural types of weight values each of which corresponds to a link and which are provided in a subscriber accommodated in the routing device, to the next routing devices to obtain the plural types of weight values for all links of the IP network, computing total weight values for all possible routes from the routing device to one of the other routing device by referring to the obtained plural types of weight values, and storing the computed total weight values for each route.
According to a twentieth aspect of the invention, there is provided a program Product comprising, computer readable instructions and a recording medium bearing the computer readable instructions. And the instructions are adaptable to enable a computer to perform a method of an IP routing computation on establishing a connection between subscribers in routing devices which are included in an IP network and are connected each other via links. The method comprises the steps of exchanging plural types of weight values each of which corresponds to a link and which are provided in a subscriber accommodated in the routing device, to the next routing devices to obtain the plural types of weight values for all links of the IP network, computing total weight values for all possible routes from the routing device to one of the other routing devices by referring to the obtained plural types of weight values, and storing the computed total weight values for each route.